Hello Peter, On Sat, 2010-11-13 at 20:20 +0100, Peter Zijlstra wrote: > On Thu, 2010-11-11 at 18:03 +0100, Michael Holzheu wrote: > > As clock for 'now' and 'time' the sched_clock() function is used and the patch > > > + preempt_disable(); > > + stats->time_ns = sched_clock(); > > + preempt_enable(); > > > + task_snap_time = sched_clock(); > > That's just plain broken... What exactly do you mean? Do you mean that we should not use sched_clock() in general or that it is called twice? > > > > + t->sched_info.last_depart = task_rq(t)->clock; > > Are you sure you don't mean task_rq(t)->clock_task ? Maybe... I want to save in "last_depart" a sched_clock() timestamp that is as precise as possible. We use "last_depart" for the TASKSTATS_CMD_ATTR_PIDS command to find out which tasks have been running on a CPU since the last taskstats snapshot. We return all tasks where last_depart > MIN(stats->time_ns for all tasks of last snapshot). Michael -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
